Built-in drive LED lamp tube with current input end

Abstract

The utility model discloses a built-in drive LED lamp tube with a current input end, which comprises a tube body, a constant current drive circuit and an LED light emitting circuit, the constant current drive circuit and the LED light emitting circuit are arranged in the tube body, two voltage lamp pins at one end of the tube body are used for being connected with commercial power, and two current lamp pins at the other end of the tube body are used for being connected with direct current. When the two voltage lamp pins are connected with alternating current voltage of the mains supply, the constant current driving circuit converts the alternating current voltage of the mains supply into direct current to drive the LED light-emitting circuit to emit light, and when the two current lamp pins are connected with direct current provided by an external power supply, the direct current directly drives the LED light-emitting circuit to emit light. The LED lamp tube has the advantages that the two current pins of the lamp tube can be directly matched with the external power supply with constant power / constant current output, direct current output by the external power supply is used for driving the LED light-emitting circuit to emit light, and therefore the output characteristic of the external power supply does not need to be compatible with a constant current driving circuit, and the LED lamp tube has a wide application range.

Description

Technical Field

[0001] The utility model relates to an LED lamp tube, in particular to a built-in drive LED lamp tube with a current input end. Background Art

[0002] The existing built-in drive LED lamp tube is of a tubular structure, usually including a tube body, a constant current drive circuit and an LED lighting circuit. The constant current drive circuit and the LED lighting circuit are arranged inside the tube body, and both ends of the tube body have two lamp pins. The existing built-in drive LED lamp tube has two forms of voltage access, namely double-end access voltage and single-end access voltage. According to its voltage access form, it is divided into two categories: double-end access lamp tubes and single-end access lamp tubes. In the double-end access lamp tube, at least one lamp pin at one end of the tube body is used to connect to the live wire of the mains electricity, and at least one lamp pin at the other end is used to connect to the neutral wire of the mains electricity. In the single-end access lamp tube, the two lamp pins at one end of the tube body are used to connect to the live wire and the neutral wire of the mains electricity respectively, and the two lamp pins at the other end are left floating and not connected to the internal circuit. When the two lamp pins used to connect to the mains electricity in the existing built-in drive LED lamp tube are connected to the mains AC voltage, the constant current drive circuit converts the mains AC voltage connected by the two lamp pins into a direct current to drive the LED lighting circuit to emit light.

[0003] At present, the built-in drive LED lamp tube usually needs to be used in combination with other types of external power supplies with constant current or constant power output, such as being used in combination with an external emergency power supply to form an LED lamp with emergency lighting function.

[0004] When the built-in drive LED lamp tube and the external emergency power supply are combined into an LED lamp with emergency lighting function, the external emergency power supply is arranged outside the built-in drive LED lamp tube, and its positive output end and negative output end are respectively connected to the two lamp pins used to connect to the mains electricity of the built-in drive LED lamp tube in a one-to-one correspondence. When the mains electricity is normal, the two lamp pins used to connect to the mains electricity of the built-in drive LED lamp tube are connected to the mains AC voltage. At this time, the constant current drive circuit converts the mains AC voltage connected by the two lamp pins into a direct current to drive the LED lighting circuit to emit light, and the built-in drive LED lamp tube realizes normal lighting. When the mains electricity is abnormally cut off, the two lamp pins used to connect to the mains electricity of the built-in drive LED lamp tube are connected to the direct current provided by the external emergency power supply. The direct current is converted by the constant current drive circuit and then drives the LED lighting circuit to emit light, and the built-in drive LED lamp tube realizes emergency lighting. The direct current provided by the external emergency power supply is the direct current obtained by converting the electrical energy of its internal storage battery, and the maximum voltage output by the external emergency power supply is equivalent to the magnitude of the mains AC voltage.

[0005] An external emergency power supply has the characteristic of a large battery capacity compared with an internal emergency power supply. Therefore, when it is used to achieve emergency lighting, it has the advantages of a large output power and a long maintenance time. However, the power output by the external emergency power supply is usually less than the power when the built-in drive LED tube is connected to the mains AC voltage. When the built-in drive LED tube is used for emergency lighting, it is required that the built-in drive LED tube can automatically reduce its power to be consistent with the power output by the external emergency power supply, so that the built-in drive LED tube can maintain stable light emission when connected at a lower power.

[0006] Therefore, in practical applications, if there is an external power supply cooperating with a built-in drive LED tube, to use the LED lighting circuit inside the built-in drive LED tube to emit light for emergency lighting, it is necessary to consider whether its output characteristics are compatible with the constant current drive circuit inside the built-in drive LED tube. Only when its output characteristics are compatible with the constant current drive circuit inside the built-in drive LED tube, can the constant current drive circuit convert the DC current it outputs to supply power to the LED lighting circuit and drive the LED lighting circuit to emit light stably. As a result, the scope of use of the built-in drive LED tube is greatly restricted. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a built-in drive LED tube with a current input end that can cooperate with an external power supply with constant power / constant current output, and can use the DC current output by the external power supply to drive the LED lighting circuit to emit light without converting the DC signal output by the external power supply through a constant current drive circuit, so that it does not require the output characteristics of the external power supply to be compatible with the constant current drive circuit, and has a wide range of use.

[0008] The technical solution adopted by the present invention to solve the above technical problem is: a built-in drive LED tube with a current input end, including a tube body, a constant current drive circuit and an LED lighting circuit. The constant current drive circuit and the LED lighting circuit are both arranged inside the tube body. Both ends of the tube body have two lamp pins. The two lamp pins at one end of the tube body are used to connect to the mains, and these two lamp pins are called two voltage lamp pins. When the two voltage lamp pins are connected to the mains AC voltage, the constant current drive circuit converts the mains AC voltage connected by the two voltage lamp pins into a DC current to drive the LED lighting circuit to emit light. The two lamp pins at the other end of the tube body are called two current lamp pins, and the two current lamp pins are used to connect to the DC current for driving the LED lighting circuit to emit light.

[0009] A protection circuit is also provided inside the tube body. The constant current drive circuit, the LED lighting circuit, and the protection circuit are arranged in sequence. The constant current drive circuit is close to the two voltage pins, and the protection circuit is close to the two current pins. The constant current drive circuit has a first input terminal, a second input terminal, a positive output terminal, and a negative output terminal. When a mains AC voltage is applied between its first input terminal and second input terminal, a DC current is output between its positive output terminal and negative output terminal. The LED lighting circuit has a positive electrode and a negative electrode. When a DC current is applied between the positive electrode and negative electrode of the LED lighting circuit, the LED lighting circuit emits light. The protection circuit is a constant current input terminal protection circuit, having a first input terminal, a second output terminal, a positive output terminal, and a negative output terminal. The positive output terminal of the constant current drive circuit and the positive output terminal of the protection circuit are both connected to the positive electrode of the LED lighting circuit. The negative output terminal of the constant current drive circuit and the negative output terminal of the protection circuit are both connected to the negative electrode of the LED lighting circuit. The first input terminal and the second input terminal of the constant current drive circuit are connected to the two voltage pins in one-to-one correspondence. The first input terminal and the second input terminal of the protection circuit are connected to the two current pins in one-to-one correspondence.

[0010] The protection circuit includes a rectifier bridge stack, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a first capacitor, a first diode, a second diode, a first MOS transistor, and a second MOS transistor. The first diode is a zener diode, and the second diode is a rectifier diode. The rectifier bridge stack has two AC input pins, a positive output terminal, and a negative output terminal. One of the AC input pins of the rectifier bridge stack is the first input terminal of the protection circuit, and the other AC input pin of the rectifier bridge stack is the second input terminal of the protection circuit. The positive output terminal of the rectifier bridge stack, one end of the first resistor, one end of the third resistor, and the positive electrode of the second diode are connected. The negative electrode of the second diode is the positive output terminal of the protection circuit. The other end of the first resistor, one end of the second resistor, one end of the first capacitor, and the gate of the first MOS transistor are connected. The other end of the third resistor, the drain of the first MOS transistor, the negative electrode of the first diode, one end of the fourth resistor, and the gate of the second MOS transistor are connected. The drain of the second MOS transistor is the negative output terminal of the protection circuit. The source of the second MOS transistor and one end of the fifth resistor are connected. The other end of the second resistor, the other end of the fourth resistor, the other end of the fifth resistor, the positive electrode of the first diode, the other end of the first capacitor, the source of the first MOS transistor, and the negative output terminal of the rectifier bridge stack are connected.

[0011] The described constant current drive circuit includes a buck constant current circuit that drives an LED lighting circuit to emit light in a buck mode and an anti-backflow diode. The anti-backflow diode is a rectifying diode. The buck constant current circuit has a live wire input terminal, a neutral wire input terminal, a positive output terminal, and a negative output terminal. The live wire input terminal and the neutral wire input terminal of the buck constant current circuit are respectively the first input terminal and the second input terminal of the constant current drive circuit. The positive output terminal of the buck constant current circuit is connected to the positive electrode of the anti-backflow diode. The negative electrode of the anti-backflow diode is the positive output terminal of the constant current drive circuit. The negative output terminal of the buck constant current circuit is the negative output terminal of the constant current drive circuit.

[0012] Compared with the prior art, the advantages of the present utility model are as follows: By using the two current lamp pins at the other end of the tube body where the single end is connected to the lamp as current input terminals for connecting the DC current that drives the LED lighting circuit to emit light. When the two voltage lamp pins are connected to the mains AC voltage, the constant current drive circuit converts the mains AC voltage into a DC current to drive the LED lighting circuit to emit light. When the two current lamp pins are connected to the DC current provided by an external power supply, this DC current drives the LED lighting circuit to emit light. Thus, the built-in drive LED tube with current input terminals of the present utility model can cooperate with an external power supply with a constant power / constant current output. Without converting the DC signal output by the external power supply through the constant current drive circuit, it can use the DC current output by the external power supply to drive the LED lighting circuit to emit light. Therefore, it does not require the output characteristics of the external power supply to be compatible with the constant current drive circuit and has a wide application range. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a structural diagram of the built-in drive LED tube with current input terminals of the present utility model;

[0014] Figure 2 is a circuit diagram of the protection circuit of the built-in drive LED tube with current input terminals of the present utility model;

[0015] Figure 3 is a structural diagram of the constant current drive circuit of the built-in drive LED tube with current input terminals of the present utility model. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0016] The following further describes the present utility model in detail with reference to the embodiments of the drawings.

[0017] Embodiment 1: As Figure 1As shown, an internally-driven LED tube with a current input terminal includes a tube body, a constant current drive circuit, and an LED lighting circuit. Both the constant current drive circuit and the LED lighting circuit are disposed inside the tube body. Both ends of the tube body each have two lamp pins. The two lamp pins at one end of the tube body are used to connect to the mains power supply, and these two lamp pins are referred to as two voltage lamp pins. When the two voltage lamp pins are connected to the mains AC voltage, the constant current drive circuit converts the mains AC voltage connected by the two voltage lamp pins into a direct current to drive the LED lighting circuit to emit light. The two lamp pins at the other end of the tube body are referred to as two current lamp pins, and the two current lamp pins are used to connect to the direct current that drives the LED lighting circuit to emit light.

[0018] In this embodiment, the two current lamp pins at the other end of the tube body with single-ended access to the tube are used as the current input terminals for connecting to the direct current that drives the LED lighting circuit to emit light. When the two voltage lamp pins are connected to the mains AC voltage, the constant current drive circuit converts the mains AC voltage into a direct current to drive the LED lighting circuit to emit light. When the two current lamp pins are connected to the direct current provided by an external power supply, this direct current drives the LED lighting circuit to emit light. Thus, the internally-driven LED tube with a current input terminal of the present utility model can cooperate with an external power supply with constant power / constant current output. Without converting the direct current signal output by the external power supply through the constant current drive circuit, it can utilize the direct current output by the external power supply to drive the LED lighting circuit to emit light, thereby eliminating the need for the output characteristics of the external power supply to be compatible with the constant current drive circuit and having a wider range of use.

[0019] Embodiment 2: This embodiment is basically the same as Embodiment 1, except that: in this embodiment, a protection circuit is further disposed inside the tube body. The constant current drive circuit, the LED lighting circuit, and the protection circuit are arranged in sequence. The constant current drive circuit is close to the two voltage lamp pins, and the protection circuit is close to the two current lamp pins. The constant current drive circuit has a first input terminal, a second input terminal, a positive output terminal, and a negative output terminal. When a mains AC voltage is connected between its first input terminal and second input terminal, a direct current is output between its positive output terminal and negative output terminal. The LED lighting circuit has a positive electrode and a negative electrode. When a direct current is connected between the positive electrode and negative electrode of the LED lighting circuit, the LED lighting circuit emits light. The protection circuit is a constant current input terminal protection circuit, having a first input terminal, a second output terminal, a positive output terminal, and a negative output terminal. The protection circuit has multiple protection functions to avoid the phenomenon that the LED tube of the present utility model may be electrically shocked or damaged during installation. The positive output terminal of the constant current drive circuit and the positive output terminal of the protection circuit are both connected to the positive electrode of the LED lighting circuit. The negative output terminal of the constant current drive circuit and the negative output terminal of the protection circuit are both connected to the negative electrode of the LED lighting circuit. The first input terminal and second input terminal of the constant current drive circuit are connected to the two voltage lamp pins in one-to-one correspondence. The first input terminal and second input terminal of the protection circuit are connected to the two current lamp pins in one-to-one correspondence.

[0020] In this embodiment, when the two voltage pins of the built-in drive LED lamp tube with a current input terminal of the present utility model are connected to the mains AC voltage, the constant current drive circuit converts the mains AC voltage into a DC current to drive the LED lighting circuit to emit light. When the two current pins of the built-in drive LED lamp tube with a current input terminal of the present utility model are connected to the DC current provided by an external power supply, the positive output terminal of the protection circuit outputs a positive current, and its negative output terminal outputs a negative current to drive the LED lighting circuit to emit light; one end of the connecting wire of the positive electrode of the LED lighting circuit is connected to the positive output terminal of the constant current drive circuit, and the other end is connected to the positive output terminal of the protection circuit. One end of the connecting wire of the negative electrode of the LED lighting circuit is connected to the negative output terminal of the constant current drive circuit, and the other end is connected to the negative output terminal of the protection circuit. Thus, in actual use, the LED lighting circuit can be connected to the constant current drive circuit and the protection circuit by routing on the PCB board where the constant current drive circuit, the LED lighting circuit, and the protection circuit are located, so that no additional routing is required, and the size of the used PCB board can be reduced.

[0021] Embodiment 3: This embodiment is basically the same as Embodiment 2, the difference being that: in this embodiment, as Figure 2 shown, the protection circuit includes a rectifier bridge stack DB1, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a first capacitor C1, a first diode D1, a second diode D2, a first MOS transistor Q1, and a second MOS transistor Q2. The first diode D1 is a zener diode, and the second diode D2 is a rectifier diode. The rectifier bridge stack DB1 has two AC input pins, a positive output terminal, and a negative output terminal. One of the AC input pins of the rectifier bridge stack DB1 is the first input terminal of the protection circuit, and the other AC input pin of the rectifier bridge stack DB1 is the second input terminal of the protection circuit. The positive output terminal of the rectifier bridge stack DB1, one end of the first resistor R1, one end of the third resistor R3, and the positive electrode of the second diode D2 are connected. The negative electrode of the second diode D2 is the positive output terminal of the protection circuit. The other end of the first resistor R1, one end of the second resistor R2, one end of the first capacitor C1, and the gate of the first MOS transistor Q1 are connected. The other end of the third resistor R3, the drain of the first MOS transistor Q1, the negative electrode of the first diode D1, one end of the fourth resistor R4, and the gate of the second MOS transistor Q2 are connected. The source of the second MOS transistor Q2 is the negative output terminal of the protection circuit. The source of the second MOS transistor Q2 and one end of the fifth resistor R5 are connected. The other end of the second resistor R2, the other end of the fourth resistor R4, the other end of the fifth resistor R5, the positive electrode of the first diode D1, the other end of the first capacitor C1, the source of the first MOS transistor Q1, and the negative output terminal of the rectifier bridge stack DB1 are connected.

[0022] In this embodiment, in addition to being able to automatically convert the polarities of the currents applied to its first input terminal and second input terminal, the protection circuit also has overvoltage protection and current limiting functions. And when the voltage magnitude between the first input terminal and the second input terminal of the protection circuit is zero, no current path can be formed from its positive output terminal and negative output terminal to its first input terminal and second input terminal, that is, current cannot flow from its positive output terminal and negative output terminal to its first input terminal and second input terminal. When installing the built-in drive LED lamp tube with current input terminals of the present invention, even if its two voltage pins are connected to the mains voltage, installers will not get an electric shock if they accidentally touch its two current pins.

[0023] In this embodiment, when the built-in drive LED lamp tube with current input terminals of the present invention and the lamp socket for installing the LED lamp tube are used together to form an LED lamp that can replace the LED lamp tube, one end of the cooperating lamp socket provides the mains voltage, and the other end can provide a constant current similar to the output of an external emergency power supply. When the built-in drive LED lamp tube with current input terminals of the present invention is accurately installed on the matching lamp socket, its two voltage pins are connected to the end of the lamp socket that provides the mains voltage, and its two current pins are connected to the end of the lamp socket that provides current for the external power supply. When installing the built-in drive LED lamp tube with current input terminals of the present invention, if its two current pins are wrongly connected to the end of the lamp socket that provides the mains voltage, the protection circuit of the built-in drive LED lamp tube with current input terminals of the present invention will either enter the overvoltage protection state or be in the current limiting state, and the built-in drive LED lamp tube with current input terminals of the present invention will not be damaged in both states.

[0024] Embodiment 4: This embodiment is basically the same as Embodiment 2, the difference being that: in this embodiment, as Figure 3 shown, the constant current drive circuit includes a buck constant current circuit that drives the LED lighting circuit to emit light in a buck mode and an anti-backflow diode D3. The anti-backflow diode D3 is a rectifier diode. The buck constant current circuit has a live wire input terminal, a neutral wire input terminal, a positive output terminal, and a negative output terminal. The live wire input terminal and the neutral wire input terminal of the buck constant current circuit are respectively the first input terminal and the second input terminal of the constant current drive circuit. The positive output terminal of the buck constant current circuit is connected to the positive electrode of the anti-backflow diode D3, the negative electrode of the anti-backflow diode D3 is the positive output terminal of the constant current drive circuit, and the negative output terminal of the buck constant current circuit is the negative output terminal of the constant current drive circuit.

[0025] In this embodiment, in the constant current driving circuit, when the voltage between the first input terminal and the second input terminal of the step-down constant current circuit is zero, the current cannot conduct from the positive output terminal and the negative output terminal of the step-down constant current circuit to its first input terminal and second input terminal. At this time, no current path can be formed from its positive output terminal and negative output terminal to its first input terminal and second input terminal, that is, the current cannot flow from its positive output terminal and negative output terminal to its first input terminal and second input terminal. When installing the built-in driving LED lamp tube with a current input terminal of the present invention, even if the two current pins are connected to the mains voltage, the installer will not be electrocuted if they accidentally touch the two voltage pins.

[0026] If the built-in driving LED lamp tube with a current input terminal of the present invention is wrongly installed on a lamp socket for a double-ended access lamp tube that does not match, then the mains voltage is connected between the two voltage pins and the two current pins of the built-in driving LED lamp tube with a current input terminal of the present invention. Since only one of the live wire and the neutral wire of the mains is connected to the two voltage pins of the built-in driving LED lamp tube with a current input terminal of the present invention, there is no voltage between the two voltage pins, and only one of the live wire and the neutral wire of the mains is connected to the two current pins, and there is no voltage between the two current pins either. In this way, an AC cut-off state is maintained between the two voltage pins and the two current pins of the built-in driving LED lamp tube with a current input terminal of the present invention. Therefore, the built-in driving LED lamp tube with a current input terminal of the present invention does not emit light and will not be damaged.

Claims

1. An internal drive LED tube with a current input terminal, comprising a tube body, a constant current drive circuit and an LED lighting circuit. Both the constant current drive circuit and the LED lighting circuit are arranged inside the tube body. Both ends of the tube body have two lamp pins. The two lamp pins at one end of the tube body are used for connecting to the mains power supply, and these two lamp pins are called two voltage lamp pins. When the two voltage lamp pins are connected to the mains AC voltage, the constant current drive circuit converts the mains AC voltage connected by the two voltage lamp pins into a direct current to drive the LED lighting circuit to emit light, and is characterized in that The two lamp pins at the other end of the tube body are referred to as two current lamp pins, and the two current lamp pins are used to connect to a direct current for driving the LED lighting circuit to emit light.

2. The built-in drive LED lamp tube with a current input end according to claim 1, wherein A protection circuit is further provided inside the tube body. The constant current driving circuit, the LED lighting circuit, and the protection circuit are arranged in sequence. The constant current driving circuit is close to the two voltage lamp pins, and the protection circuit is close to the two current lamp pins. The constant current driving circuit has a first input terminal, a second input terminal, a positive output terminal, and a negative output terminal. When a mains AC voltage is connected between its first input terminal and second input terminal, a direct current is output between its positive output terminal and negative output terminal. The LED lighting circuit has a positive electrode and a negative electrode. When a direct current is connected between the positive electrode and negative electrode of the LED lighting circuit, the LED lighting circuit emits light. The protection circuit is a constant current input terminal protection circuit, having a first input terminal, a second output terminal, a positive output terminal, and a negative output terminal. The positive output terminal of the constant current driving circuit and the positive output terminal of the protection circuit are both connected to the positive electrode of the LED lighting circuit. The negative output terminal of the constant current driving circuit and the negative output terminal of the protection circuit are both connected to the negative electrode of the LED lighting circuit. The first input terminal and the second input terminal of the constant current driving circuit are respectively and correspondingly connected to the two voltage lamp pins. The first input terminal and the second input terminal of the protection circuit are respectively and correspondingly connected to the two current lamp pins.

3. The built-in drive LED tube with a current input terminal according to claim 2, characterized in that The protection circuit includes a rectifier bridge stack, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a first capacitor, a first diode, a second diode, a first MOS transistor, and a second MOS transistor. The first diode is a voltage stabilizing diode, and the second diode is a rectifier diode. The rectifier bridge stack has two AC input pins, a positive output terminal, and a negative output terminal. One of the AC input pins of the rectifier bridge stack is the first input terminal of the protection circuit, and the other AC input pin of the rectifier bridge stack is the second input terminal of the protection circuit. The positive output terminal of the rectifier bridge stack, one end of the first resistor, one end of the third resistor, and the positive electrode of the second diode are connected. The negative electrode of the second diode is the positive output terminal of the protection circuit. The other end of the first resistor, one end of the second resistor, one end of the first capacitor, and the gate of the first MOS transistor are connected. The other end of the third resistor, the drain of the first MOS transistor, the negative electrode of the first diode, one end of the fourth resistor, and the gate of the second MOS transistor are connected. The drain of the second MOS transistor is the negative output terminal of the protection circuit. The source of the second MOS transistor and one end of the fifth resistor are connected. The other end of the second resistor, the other end of the fourth resistor, the other end of the fifth resistor, the positive electrode of the first diode, the other end of the first capacitor, the source of the first MOS transistor, and the negative output terminal of the rectifier bridge stack are connected.

4. A built-in drive LED lamp tube with a current input end according to claim 2, characterized in that The described constant current driving circuit includes a buck constant current circuit that drives an LED lighting circuit to emit light in a buck mode and an anti-backflow diode. The anti-backflow diode is a rectifier diode. The buck constant current circuit has a live wire input terminal, a neutral wire input terminal, a positive output terminal, and a negative output terminal. The live wire input terminal and the neutral wire input terminal of the buck constant current circuit are respectively the first input terminal and the second input terminal of the constant current driving circuit. The positive output terminal of the buck constant current circuit is connected to the positive electrode of the anti-backflow diode. The negative electrode of the anti-backflow diode is the positive output terminal of the constant current driving circuit. The negative output terminal of the buck constant current circuit is the negative output terminal of the constant current driving circuit.

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